If you decide to wait until a later potty training age, you can still put this time to good use. The interval between 12-18 months is the perfect time to start thinking about toilet readiness--a set of skills and interests that will help your child master advanced toilet skills later on (see below).
Vertebrate Flight. PTEROSAURIAN FLIGHT. The first vertebrates to evolve true flight were the pterosaurs, flying archosaurian reptiles. After the discovery of pterosaur fossils in the 18th century, it was thought that pterosaurs were a failed experiment in flight, or that they were simply gliders, too weak to fly.
These soft bodied animals , like the fungi, existed in the Ediacaran period (late- Precambrian) about 560 mya. The earliest known chordates, animals with notochords and thus ancestors of vertebrate , were Pikaia. Chordate fossils are found in the Burgess Shale and are approximately 530 million years old.